Supervisor

Helmut HABERSACK, https://orcid.org/0000-0002-1598-6138

Content

This PhD-project analyses the interaction of extreme discharges with sediment transport and morphodynamis, focusing of the following questions:

1) What is the role of extreme floods for turbulent flow, sediment transport and morphodynamics?

2) How are these processes affecting people and lead to human infrastructure damages during extreme events and how large should a river morphological space demand be?

3) Conversely, how do changes in sediment regimes (due to human intervention) affect flood risk?

Skills and Qualifications

  • Required: Master or other equivalent university degree in Environmental Engineering, Civil Engineering, Water Management, other natural and technical sciences
  • Desirable: experience with floodrisk, river morphology, sediment transport, physical and numerical modelling
 

 

Introduction/background

Extreme events like large floods play an essential role for IRL since they determine central boundary conditions for the river development like sediment transport, river morphology, including width, depth and their dynamics, slope and grain size. Extreme events cause casualties, huge economic damages and are directly related to human activities and their history. Extreme events over the last 20 years demonstrated the limits of flood protection and that failures might even lead to large damages in protected areas. Floods affected around two billion people from 1997 to 20173 and floods cause an annual average loss of US$ 104 billion worldwide4. However, central processes that lead to casualties and economic damages are not fully understood.

Main objective/research question/hypothesis

The main objective is to analyse the effects of extreme floods that occurred in the last decades in Austria and of simulated floods concerning their effects on sediment transport and morphodynamics, leading to casualties and structural damages. The main research questions are:
1) What is the role of extreme floods for turbulent flow, sediment transport and morphodynamics?
2) How are these processes affecting people and lead to human infrastructure damages during extreme events and how large should a river morphological space demand be?
3) Conversely, how do changes in sediment regimes (due to human intervention) affect flood risk?

Approach/methods and time frame

Based on flood documentations, data on sediment transport and morphological changes will be quantitatively analysed (M0-12). Thereby suspended sediment and bedload fluxes, cross sectional changes and morphodynamics will be related (i) to hydrodynamics, sediment supply, sediment balance and (ii) to occurring casualties and damages (socio-economic dimension). For representative events and 3 pilot sites 3D numerical modelling will allow to quantify physical processes (M13-24). In the unique BOKU Hydraulic Engineering Laboratory, allowing free flowing discharge of up to 10 m3s-1 and 3 m water depth, fundamental investigations of flood effects on sediment transport, morphodynamics and human drift risk will be done, including a variation of different boundary conditions (e.g. sediment supply) (M25-M48).